Spinning Disc Pointer in Finder. Machine stalls.

Question

I'm experiencing a really slow running MBP 15inch early 2011. It's driving me nuts.
I'm not a complete Mac noob and have been working with them since SE30 days, so am usually able to help myself quite a lot in the
few instances when I encounter issues.
The computer starts up to the Finder, but then seems to stall intermittently inside the Finder environment, producing the spinning disc pointer.
Single or double clicking on file icons on the Desktop, trying to open the Hard Disk drive, trying to open Firefox/Safari, Word, Outlook,
or any other application, or going into any of the menus inside the Finder produces the Spinning Disc pointer for about 60-90 seconds each time.
It's driving me crazy and we need this machine for work!
Yesterday I thought it may be a virus (as unlikely as it seems) so I tried installing Sophos AV. The installation process took forever...I'm talking
a good 30-40 minutes here. This isn't normal.
After it was installed, I did a complete disk scan and no virus was found. The scan itself seemed to progress at a normal speed, so during this process
no stalls were encountered.
I check the process monitor and everything seems normal. No application or process is hogging the CPU and everything seems to be running
in norm params. When the spinning disc pointer appears in the Finder, I am however unable to access the Apple process monitor, since the pointer has to be normally triggered in the Finder and then it prevents you from switching to the Process Monitor in order to monitor what's going on.
Frustrating.
We had this issue about 1-2 months ago on the same machine. I erased and re-installed the OS and this is has now been running on 10.8.2.
We work a lot with media files, so at the same time I thought I'd upgrade the machine from 8Gb to 16Gb RAM to rule out the issue of any RAM
related bottlenecks and provide more operating space/capability within the applications.
I also downloaded and ran iDefrag to make sure the HD was in a good state.
The problem then disappeared and it has been working fine for a while.
Last week, the issue suddenly returned. All of a sudden, it's beginning to lock up again. Randomly. It may work now, but after the next restart it's almost
unuseable.
I ran the Repair Disk Permissions command inside Disk Utility and this did find some incorrect permission settings, which it repaired. It hasn't
helped the machine though, and this is still running like a Mac Plus in the olden days.
Another thing I noticed, running the Software update, produces the AppStore application, but this also stalls and doesn't even redraw the contents of the Appstore, so I am no longer able to see if there are any updates waiting let alone browse through the store. I just get placeholders and incomplete
constructed pages (much like when a web page doesn't load properly).
I don't think it's software related as it has obviously worked for a while and has now appeared suddenly again. We haven't installed anything, apart
from the Sophos AV yesterday which didn't produce any findings.
Is the hard disk on it's way out perhaps? I know from experience that HDs get slow, produce intermittent issues and then start failing.
I find this unlikely though, as the HD and other hardware is only about 2 years old.
anyone have any ideas what's going on?

Answer 1

The next time you have the problem, note the exact times when it starts and ends: hour, minute, second.
If you have more than one user account, these instructions must be carried out as an administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.
Scroll back in the log to the time you noted above. Post any messages timestamped during that interval – the text, please, not a screenshot.
When posting a log extract, be selective. In most cases, a few dozen lines are more than enough.
Please do not indiscriminately dump thousands of lines from the log into a message.
Important: Some private information, such as your name, may appear in the log. Edit it out by search-and-replace in a text editor before posting.